Abstract

Germ cell apoptosis have been recognized as an important event in order to regulate daily sperm production in humans and in animal models as well. Several studies in rat, mouse and monkeys have shown that testicular mild heat stress (43°C for 15 min) induces a massive increase in germ cell apoptosis along with oxidative damage and activation of diverse signaling pathways. In addition, heat stress produces a decrease in sperm viability, increase sperm damage and decrease embryo quality. In human, testis exposure to heat stress may result from occupational exposure, life style or clinical disorders including cryptorchidism or varicocele. Thus, in the past years researchers have focused on two major areas; the first is to find the molecular signaling pathway trigger by heat stress, and 2) to seek for new molecules with antioxidant abilities which may prevent germ cell apoptosis and/or to improve sperm performance. However, the link between heat stress and male infertility in humans still remains controversial. Here we critically review the available literature in human and animal models, and we propose a new model which explain the elevate apoptosis rate and sperm damage observed after heat stress. Finally we review the available data in pharmacological therapies to protect testicular damage from heat stress